1. Field of Invention
The present invention relates to a pixel structure and a liquid crystal display panel. More particularly, the present invention relates to a pixel structure and a liquid crystal display panel having transition electrode.
2. Description of Related Art
As the demand for display devices increases, the efforts dedicated to the development of the relative display devices have been made. Wherein, the cathode ray tube (CRT) has been dominating the display device market for its excellent display quality and mature d technology. However, recently, with the rise of the green environment protection concept, coupled with the disadvantage of high power consumption and high radiation, plus the limited flat panel design capability, CRT can not meet the requirements of the market trend for light, thin, short, small, and power-saving display product. Therefore, the thin film transistor liquid crystal display (TFT-LCD), having such advantages as high image quality, high space utilization efficiency, low power consume, and no radiation, has become the main stream product in the market.
The liquid crystal display devices can be divided into different types according to the type of the liquid crystal, the driving method and the configuration position of the light source. Wherein, the optically compensated birefringence liquid crystal display (OCB LCD), with quick response speed, can provide the computer with smoother image presentation while displaying continuous quickly changing images, such as cartoons or films. The OCB LCD is suitable for high-end liquid crystal display (LCD) device. However, only after part of the liquid crystal molecules are transformed into a twist state from a splay state, then, transformed into a bend state, the OCB LCD can enter standby status to provide quick response operation.
FIG. 1A is a schematic diagram of the liquid crystal molecules in a splay state in a liquid crystal display panel. FIG. 1B is a schematic diagram of the liquid crystal molecule in a bend state in a liquid crystal display panel. Referring to FIG. 1A and FIG. 1B simultaneously, in the OCB LCD panel 10, the liquid crystal layer 11 is disposed between the upper substrate 12 and the lower substrate 13. The rubbing directions of the alignment layers disposed on the upper substrate 12 and the lower substrate 13 are parallel. When the liquid crystal molecules in the liquid crystal layers 11 are not affected by external electric fields, they are arranged in a splay state. When the OCB LCD device turns into a standby status, an electric field perpendicular to the upper substrate 12 must be applied on the liquid crystal molecules. Accordingly, parts of the liquid crystal molecules are transformed into a bend state. In the conventional OCB LCD devices, in order to drive the pixels normally, it may need several minutes to perform the transforming process; that is, a long warming-up is required before the OCB LCD turns into a standby status. However, it works against the open-and-play characteristic necessary for the liquid crystal displays. Therefore, in order for the OCB LCD devices to be more acceptable by the consumers, fast transition is necessary.
In order to have the liquid crystal molecules in the OCB LCD panel transform to a bend state from a splay state quickly, a conventional technology is to generate stronger electric field by increasing the voltage, so that the liquid crystal molecules can be transformed to a bend state from a splay state quickly. However, it is not easy to find the suitable driving chip which can bear the high voltage, and it is not easy to conduct the related research and development. Another common method in the conventional technology is by adding polymer in the liquid crystal layer. When the liquid crystal molecules are in a bend state, the ultraviolet radiation is radiated on the polymer to form a high molecule wall. Accordingly, the liquid crystal molecules can be kept to be arranged in a bend state. Although the method is simple, it will result in light leakage in the OCB LCD panel. In addition, in other conventional methods, for example, slits are formed in the pixel electrode or bumps are formed above the pixel electrode by a special pixel design. Accordingly, the arrangement type of the liquid crystal molecules in the partial region can be changed, to accelerate the process of the transition from a splay state to a bend state.